如何在java中渲染图像上的包装文本

Question

使用Java，是否有任何内置的方式来呈现文本，使其仅限于graphics2D对象上的矩形？

我知道我可以使用Graphics2D.drawString，但它只会画出一行文字。

我也知道我可以使用

FontMetrics fm= graphics.getFontMetrics(font);
Rectangle2D rect=fm.getStringBounds("Some Text",graphics);

在某些Font font对象上使用某些Graphics2D graphics呈现时获取有关字符串边界的信息。

所以我可以开始循环，打破我的字符串等等以强制它适合某个矩形。

但我更不愿意写那些......

有没有现成的功能可以帮我吗？

Answer 1

我写了一个可以提供帮助的小功能。 447是可用宽度，您可以从所需宽度获得以呈现文本。

private void drawTextUgly(String text, FontMetrics textMetrics, Graphics2D g2)
{
    // Ugly code to wrap text
    int lineHeight = textMetrics.getHeight();
    String textToDraw = text;
    String[] arr = textToDraw.split(" ");
    int nIndex = 0;
    int startX = 319;
    int startY = 113;
    while ( nIndex < arr.length )
    {
        String line = arr[nIndex++];
        while ( ( nIndex < arr.length ) && (textMetrics.stringWidth(line + " " + arr[nIndex]) < 447) )
        {
            line = line + " " + arr[nIndex];
            nIndex++;
        }
        GraphicsUtility.drawString(g2, line, startX, startY);
        startY = startY + lineHeight;
    }
}

Answer 2

这可能就是你要找的东西：

<强> StringUtils.java：

import java.awt.FontMetrics;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

/**
 * Globally available utility classes, mostly for string manipulation.
 * 
 * @author Jim Menard, <a href="mailto:jimm@io.com">jimm@io.com</a>
 */
public class StringUtils {
  /**
   * Returns an array of strings, one for each line in the string after it has
   * been wrapped to fit lines of <var>maxWidth</var>. Lines end with any of
   * cr, lf, or cr lf. A line ending at the end of the string will not output a
   * further, empty string.
   * <p>
   * This code assumes <var>str</var> is not <code>null</code>.
   * 
   * @param str
   *          the string to split
   * @param fm
   *          needed for string width calculations
   * @param maxWidth
   *          the max line width, in points
   * @return a non-empty list of strings
   */
  public static List wrap(String str, FontMetrics fm, int maxWidth) {
    List lines = splitIntoLines(str);
    if (lines.size() == 0)
      return lines;

    ArrayList strings = new ArrayList();
    for (Iterator iter = lines.iterator(); iter.hasNext();)
      wrapLineInto((String) iter.next(), strings, fm, maxWidth);
    return strings;
  }

  /**
   * Given a line of text and font metrics information, wrap the line and add
   * the new line(s) to <var>list</var>.
   * 
   * @param line
   *          a line of text
   * @param list
   *          an output list of strings
   * @param fm
   *          font metrics
   * @param maxWidth
   *          maximum width of the line(s)
   */
  public static void wrapLineInto(String line, List list, FontMetrics fm, int maxWidth) {
    int len = line.length();
    int width;
    while (len > 0 && (width = fm.stringWidth(line)) > maxWidth) {
      // Guess where to split the line. Look for the next space before
      // or after the guess.
      int guess = len * maxWidth / width;
      String before = line.substring(0, guess).trim();

      width = fm.stringWidth(before);
      int pos;
      if (width > maxWidth) // Too long
        pos = findBreakBefore(line, guess);
      else { // Too short or possibly just right
        pos = findBreakAfter(line, guess);
        if (pos != -1) { // Make sure this doesn't make us too long
          before = line.substring(0, pos).trim();
          if (fm.stringWidth(before) > maxWidth)
            pos = findBreakBefore(line, guess);
        }
      }
      if (pos == -1)
        pos = guess; // Split in the middle of the word

      list.add(line.substring(0, pos).trim());
      line = line.substring(pos).trim();
      len = line.length();
    }
    if (len > 0)
      list.add(line);
  }

  /**
   * Returns the index of the first whitespace character or '-' in <var>line</var>
   * that is at or before <var>start</var>. Returns -1 if no such character is
   * found.
   * 
   * @param line
   *          a string
   * @param start
   *          where to star looking
   */
  public static int findBreakBefore(String line, int start) {
    for (int i = start; i >= 0; --i) {
      char c = line.charAt(i);
      if (Character.isWhitespace(c) || c == '-')
        return i;
    }
    return -1;
  }

  /**
   * Returns the index of the first whitespace character or '-' in <var>line</var>
   * that is at or after <var>start</var>. Returns -1 if no such character is
   * found.
   * 
   * @param line
   *          a string
   * @param start
   *          where to star looking
   */
  public static int findBreakAfter(String line, int start) {
    int len = line.length();
    for (int i = start; i < len; ++i) {
      char c = line.charAt(i);
      if (Character.isWhitespace(c) || c == '-')
        return i;
    }
    return -1;
  }
  /**
   * Returns an array of strings, one for each line in the string. Lines end
   * with any of cr, lf, or cr lf. A line ending at the end of the string will
   * not output a further, empty string.
   * <p>
   * This code assumes <var>str</var> is not <code>null</code>.
   * 
   * @param str
   *          the string to split
   * @return a non-empty list of strings
   */
  public static List splitIntoLines(String str) {
    ArrayList strings = new ArrayList();

    int len = str.length();
    if (len == 0) {
      strings.add("");
      return strings;
    }

    int lineStart = 0;

    for (int i = 0; i < len; ++i) {
      char c = str.charAt(i);
      if (c == '\r') {
        int newlineLength = 1;
        if ((i + 1) < len && str.charAt(i + 1) == '\n')
          newlineLength = 2;
        strings.add(str.substring(lineStart, i));
        lineStart = i + newlineLength;
        if (newlineLength == 2) // skip \n next time through loop
          ++i;
      } else if (c == '\n') {
        strings.add(str.substring(lineStart, i));
        lineStart = i + 1;
      }
    }
    if (lineStart < len)
      strings.add(str.substring(lineStart));

    return strings;
  }

}

你把它放在自己的课堂上，然后简单地使用你拥有的东西：

FontMetrics fm= graphics.getFontMetrics(font);
Rectangle2D rect=fm.getStringBounds("Some Text",graphics);

致电wrap(String str, FontMetrics fm, int maxWidth)，该List会返回String maxWidth个已Rectangle2D的{​​{1}}个String text="Some Text"; FontMetrics fm= graphics.getFontMetrics(font); Rectangle2D rect=fm.getStringBounds(text,graphics); List<String> textList=StringUtils.wrap(text, fm, int maxWidth); 相应的{{1}} {{1}}宽度{{1}}文字将被放入：

{{1}}

<强>参考：

• http://www.java2s.com/Code/Java/2D-Graphics-GUI/WrapstringaccordingtoFontMetrics.htm

Answer 3

请参阅this answer中的LabelRenderTest来源。它使用HTML / CSS，使用CSS设置主体宽度，从而自动换行。

Answer 4

 private List<String> wrap(String txt, FontMetrics fm, int maxWidth){
    StringTokenizer st =  new  StringTokenizer(txt)  ;

    List<String> list = new ArrayList<String>();
    String line = "";
    String lineBeforeAppend = "";
    while (st.hasMoreTokens()){
       String seg = st.nextToken();
       lineBeforeAppend = line;
       line += seg + " ";
       int width = fm.stringWidth(line);
       if(width  < maxWidth){
           continue;
       }else { //new Line.
           list.add(lineBeforeAppend);
           line = seg + " ";
       }
    }
    //the remaining part.
    if(line.length() > 0){
        list.add(line);
    }
    return list;
}

Answer 5

使用临时 JTextArea 用约 10 行代码完成完美的换行：

static void drawWrappedText(Graphics g, String text, int x, int y, int w, int h) {
    JTextArea ta = new JTextArea(text);
    ta.setLineWrap(true);
    ta.setWrapStyleWord(true);
    ta.setBounds(0, 0, w, h);
    ta.setForeground(g.getColor());
    ta.setFont(g.getFont());
    Graphics g2 = g.create(x, y, w, h); // Use new graphics to leave original graphics state unchanged
    ta.paint(g2);
}